ESS adds 8.5 GWh of sodium-ion to its battery storage portfolio

ESS is moving beyond its long-duration energy storage roots into the crowded short- and medium-duration battery storage market – but not with lithium.

The Oregon-based company said it signed a letter of intent with Malden, Massachusetts-based Alsym Energy to add 8.5 gigawatt-hours (GWh) of sodium-ion battery cells and modules to its portfolio.

The move pushes ESS into short- and medium-duration battery storage – a segment where lithium-ion has long been the default – while building out a broader portfolio alongside its existing iron flow systems.

Why sodium-ion

Sodium-ion batteries are getting attention as a safer alternative to lithium-based chemistries. ESS says the technology it’s bringing in from Alsym is non-flammable and avoids the thermal runaway risks that have been a concern with lithium-ion systems.